African Journal of Biotechnology Full Length Research Paper

Effect of pH and temperature on the activity and 
stability of T. coremiiforme lipase 
As shown in Figure 4A, the activity of the T. coremiiforme 
lipase presents a maximum activity at pH 8.0; beyond this 
pH value, the activity of the enzyme decreased gradually. 
Also, our results show that the enzyme activity was found 
to be stable between pH 5.0 to 10.0 (Figure 4B). This 
observation is also similar to those found for other 
Trichosporons lipases (Arai et al., 1997; Dharmsthiti and 
Ammaranond, 1997).  
The effect of temperature on the activity of T.

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4508 Afr. J. Biotechnol. 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 4. pH effect on enzyme activity (A) and stability (B) of TCL. Optimal pH was determined with tributyrin at 50°C under 
standard conditions. Stability was analysed after pre-incubating the pure enzyme for 24 h in different buffer solutions at various pH 
ranging from 3 to 12; C, temperature effect on TCL activity; D, temperature effect on TCL stability. For temperature stability, the 
pure enzyme was preincubated at different temperatures for 1 h and the remaining activity was measured under the standard 
conditions. 
coremiiforme lipase was also examined in the range of 20 
to 90°C. Lipolytic activities of T. coremiiforme lipase were 
found to be profoundly affected by temperature. As 
shown in Figure 4C, the activity of lipase increased 
gradually with rise in temperature and the maximum 
activity was observed around 40 to 60°C. The activity 
decreased abruptly and the enzyme lost its activity 
almost completely at 100°C. Furthermore, the thermal 
stability of lipase was studied from 20 to 90°C. The data 
shown in Figure 4D, indicates that T. coremiiforme lipase 
has appreciable stability (50 to 90°C) after prolonged 
incubation of about 60 min. The enzyme exhibited 
maximum stability at 40 to 50°C but also found to be fairly 
stable up to 50°C with concomitant loss of activation after 
60 min incubation, and it was highly stable at 80°C with 
half-lives of 5 min.